Image forming unit with control electrodes arranged to be electrically insulated from each other

Abstract

An aperture electrode unit mounted in an image forming apparatus includes a polyimide insulating sheet, plural apertures, substantially T-shaped control electrode portions each of which is provided at a part of the peripheral edge of each aperture, and conductive wiring portions extending from the control electrode portions to the downstream side of a toner supply direction. With this construction, a minimum distance can be kept between a control electrode portion and a conductive wiring portion, which are adjacent to each other. So, no breakdown occurs, and image quality can be improved.

What is claimed is: 
     
       1. An image forming apparatus that forms an image on a supporter with toner, comprising: a toner supply that supplies charged toner to the supporter in a supply direction; and   a toner flow controller confronting the toner supply that controls a flow of charged toner from the toner supply to the supporter with selective application of an electric field, the toner flow controller having plural apertures therein aligned in at least one row that allow the charged toner to pass therethrough, the apertures being defined by an upstream peripheral edge disposed upstream of the toner supply direction, a downstream peripheral edge disposed downstream of the toner supply direction, and a pair of side edges, the toner flow controller also having a plurality of control electrodes provided on at least one of the peripheral edges of each of the apertures and having conductive wiring extending longitudinally therefrom downstream of the toner supply direction,   wherein at least a portion of the edge defining each aperture does not have a control electrode thereon; and   wherein the control electrodes are spaced from each other by at least 10 μm such that electrical discharge does not occur between adjacent control electrodes and wherein each of the control electrodes comprises a first control electrode portion extending perpendicular to the toner supply direction on a peripheral edge of one of the apertures, and at least one second control electrode portion integral with the first control electrode portion extending parallel to the toner supply direction on a peripheral edge of the aperture.   
     
     
       2. The image forming apparatus of claim 1 wherein the toner flow controller includes an insulating sheet having two opposed surfaces, wherein the control electrodes and the conductive wiring are formed on one surface of said insulating sheet and the toner supply confronts the other surface of the insulating sheet. 
     
     
       3. The image forming apparatus of claim 1 wherein the apertures are arranged in two staggered rows. 
     
     
       4. The image forming apparatus of claim 1 wherein the control electrodes are disposed on the upstream peripheral edge of the apertures. 
     
     
       5. The image forming apparatus of claim 1 wherein the control electrodes are disposed on the downstream peripheral edge of the apertures. 
     
     
       6. The image forming apparatus of claim 1 wherein the control electrodes are disposed on both the upstream and downstream peripheral edges of the apertures. 
     
     
       7. The image forming apparatus of claim 1 wherein the control electrodes are disposed on at least one side edge of the apertures. 
     
     
       8. The image forming apparatus of claim 1 wherein the control electrodes are disposed on one of the edges in the pair of side edges of the apertures, wherein adjacent apertures each have a control electrode disposed on a similarly positioned one side edge. 
     
     
       9. The image forming apparatus of claim 1 wherein the control electrodes are disposed on one side edge of the apertures, wherein adjacent apertures have a control electrode on adjacent side edges. 
     
     
       10. The image forming apparatus of claim 1 wherein the control electrodes are disposed on both side edges of the apertures. 
     
     
       11. The image forming apparatus of claim 1 wherein the control electrodes are substantially T-shaped. 
     
     
       12. The image forming apparatus of claim 1 wherein the control electrodes are substantially L-shaped. 
     
     
       13. The image forming apparatus of claim 1 wherein the control electrodes are substantially H-shaped. 
     
     
       14. The image forming apparatus of claim 1 wherein the control electrodes are substantially U-shaped. 
     
     
       15. The image forming apparatus of claim 1 wherein the apertures are rectangular. 
     
     
       16. An electrode unit for directly controlling a flow of charged particles with an electric field, comprising: an insulating member having a longitudinal axis and a plurality of aligned apertures therein, each of the apertures being defined by a peripheral edge; and   control electrodes provided on the insulating member arranged to be electrically insulated from one another and disposed on at least a part of the peripheral edge of each aperture, wherein at least a portion of the edge defining each aperture does not have a control electrode thereon, the control electrodes including conductive wiring portions extending substantially parallel to the longitudinal axis and connected to a control voltage source, wherein the control electrodes selectively apply a voltage from the control voltage source to control the flow of charged particles and are spaced from each other by at least 10 μm such that electrical discharge does not occur between adjacent control electrodes, wherein each of the control electrodes comprises a first control electrode portion extending perpendicular to the longitudinal axis on a peripheral edge of one of the apertures, and at least one second control electrode portion integral with the first control electrode portion extending parallel to the longitudinal axis on a peripheral edge of the aperture.   
     
     
       17. The electrode unit of claim 16, wherein the plurality of apertures are arranged in two staggered rows. 
     
     
       18. The electrode unit of claim 16, wherein the predetermined distance is measured from an end of one of the first control electrode portions of one control electrode to the conductive wiring of an adjacent control electrode. 
     
     
       19. The electrode unit of claim 16, wherein the predetermined distance is measured from an end of one of the first control electrode portions of one control electrode to an end of one of the first control electrode portions of an adjacent control electrode. 
     
     
       20. The electrode unit of claim 16, wherein one of the second control electrode portions is disposed directly between a pair of adjacent apertures and is located on the peripheral edge of both apertures. 
     
     
       21. The electrode unit of claim 16 wherein each of the apertures is rectangular and has an outer peripheral edge, an inner peripheral edge, and a pair of side edges, wherein the outer and inner peripheral edges extend generally perpendicular to the longitudinal direction and the side edges extend generally parallel to the longitudinal direction. 
     
     
       22. The electrode unit of claim 21 wherein the control electrodes are disposed on at least one of the outer and inner peripheral edges and at least one of the side edges of an aperture. 
     
     
       23. An electrode unit for directly controlling a flow of charged particles with an electric field, comprising: an insulating member having a longitudinal axis and a plurality of aligned apertures therein, the apertures being defined by a peripheral edge; and   control electrodes provided on the insulating member arranged to be electrically insulated from one another and disposed on at least a part of the peripheral edge of each aperture, wherein at least a portion of the edge defining each aperture does not have a control electrode thereon, the control electrodes including conductive wiring portions extending substantially parallel to the longitudinal axis, wherein the control electrodes selectively apply a voltage to control the flow of charged particles and are spaced from each other by at least 10 μm such that electrical discharge does not occur between adjacent control electrodes.   
     
     
       24. The electrode unit of claim 23, wherein each of the control electrodes comprises a first control electrode portion extending perpendicular to the longitudinal direction on a peripheral edge of one of the apertures, and at least one second control electrode portion integral with the first control electrode portion extending parallel to the longitudinal direction on a peripheral edge of the aperture. 
     
     
       25. The electrode unit of claim 24, wherein each of the control electrodes comprises a first control electrode portion extending perpendicular to the longitudinal direction on a peripheral edge of one of the apertures, and at least one second control electrode portion integral with the first control electrode portion extending parallel to the longitudinal direction on a peripheral edge of the aperture.